Help with Mathematical Solution to a Single Leg Hanging Basket

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Discussion Overview

The discussion revolves around the mathematical modeling of a single leg hanging basket, particularly focusing on the dynamics of the system, the positioning of the center of gravity, and the implications of fixed points in the setup. Participants explore the theoretical aspects of the problem, including the effects of forces and torques on the system's equilibrium.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants question the assumption that the center of gravity must be directly underneath the lifting point ML, suggesting that the tension in the rope could cause a shift in the center of gravity.
  • Others argue that if the center of gravity is not directly beneath ML, it would create a net torque due to gravity, leading to movement.
  • One participant notes that the system will hang to minimize gravitational potential energy, implying that the center of mass should align vertically with the support point.
  • There is a discussion about the dimensions of the system, with some participants highlighting the significance of the small dimensions and high density of the material involved.
  • Another point raised is that the vertical alignment of points ML, P, and G is necessary in a steady state to prevent sideways forces that would cause swinging.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of the center of gravity being directly beneath the lifting point, indicating that multiple competing perspectives remain unresolved.

Contextual Notes

Participants note the lack of specific dimensions and distances in the problem, which affects their ability to fully analyze the system's behavior.

James Hayes
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TL;DR
Picture a basket, connected to a hanging point (ML), from two fixings (F). One of these ropes connecting these points snaps, and the basket shifts and drops on one side. Resulting in the rope snagging onto a pivot point (P). We know the mass, the length of a couple dimensions. I want to know a method of calculating the angle theta, shown in the last diagram. Point F and G and P are all fixed in place and do not move. Please see PDF for more information.
1610704478272.png
1610704519940.png
 

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Hello @James Hayes , :welcome: !

Is this homework or do you consider designing a balloon with basket ?

James Hayes said:
the basket shifts and drops on one side. Resulting in the rope snagging onto a pivot point (P)
And if nothing dampens the swinging ?
(I find the "Point F and G and P are all fixed in place" pretty questionable for G !)

Never mind, I suppose you silently assume the swinging terminates, at which time G should be directly underneath ML. Right ?

PFG is a triangle that keeps its shape, but rotates. How far is undeteermined since you give no sideways distances. Additionally, ##\theta## can not be calculated as long as ML to P is unknown
 
Hi

F, G and P are fixed. But surely the center of gravity does not need to be directly underneath the lifting point ML. The black line from ML to P to F is a rope, it does not 'fix' to P, it simply is wrapped around P. Surely, the tension in the rope pulling on fixing point 'F', around pivot point p will cause the center of gravity to shift out from being directly underneath, as this creates a force in X from point F.

thank you
 
James Hayes said:
But surely the center of gravity does not need to be directly underneath the lifting point ML.
If it is not, there will be a net torque due to gravity that will cause movement, no?
 
The system will hang such as to minimize the gravitational potential energy. This requires the C M to be directly below the support, as @berkeman man has observed.

These are really small dimensions!
 
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Dr.D said:
These are really small dimensions!
Oh jeeze, I missed that. Especially small considering the mass... :wink:

1610746538408.png
 
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berkeman said:
Oh jeeze, I missed that. Especially small considering the mass... :wink:

View attachment 276314
It is just very high density material!
 
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James Hayes said:
Hi

F, G and P are fixed. But surely the center of gravity does not need to be directly underneath the lifting point ML.
Welcome, James! :cool:

On the contrary, points ML and G must be on the same vertical line.
That vertical line should intersect the line joining P and F somewhere.
That point of intersection depends on dimensions that are not provided by the problem.
For example, x and y distances between G and F or ML and F.
 
It seems to me the rope from ML to P must be vertical in the steady state, otherwise there would be a sideways force on the body and it would swing. Therefore, Theta is zero, and ML, P and G are all on the same line vertically. The angle ML-P-F is determined by geometry.
 

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